That link is may be cutting a few corners short. Though thatīs tough to prove, cos they donīt even list the countries, that for example Finns could travel without a visa, they just announce, how many there are, according to them!
Especially īVisa-on-arrivalī is something, thatīs almost guaranteed to lead to confusion. In some cases, it could be available only, when you arrive via certain entry points (usually the biggest airports), and there may be other conditions, that you need to fulfill in order to get the VOA. And these regulations change all the time. So itīs really not so simple, any list would probably be out of date within a few weeks.